diff --git a/include/secp256k1_extrakeys.h b/include/secp256k1_extrakeys.h
index deb8dc8b9..d8e05398c 100644
--- a/include/secp256k1_extrakeys.h
+++ b/include/secp256k1_extrakeys.h
@@ -242,7 +242,8 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_keypair_xonly_tweak_add
     const unsigned char *tweak32
 ) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
 
-/** Compare two public keys using lexicographic order
+/** Compare two public keys using lexicographic order of their compressed
+ *  serialization.
  *
  *  Returns: <0 if the first public key is less than the second
  *           >0 if the first public key is greater than the second
@@ -257,7 +258,8 @@ SECP256K1_API int secp256k1_pubkey_cmp(
     const secp256k1_pubkey* pk2
 ) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
 
-/** Sorts public keys using lexicographic order
+/** Sort public keys using lexicographic order of their compressed
+ *  serialization.
  *
  *  Returns: 0 if the arguments are invalid. 1 otherwise.
  *
diff --git a/src/modules/musig/keyagg_impl.h b/src/modules/musig/keyagg_impl.h
index 85bbacfa0..114c831ab 100644
--- a/src/modules/musig/keyagg_impl.h
+++ b/src/modules/musig/keyagg_impl.h
@@ -166,6 +166,12 @@ static void secp256k1_musig_keyaggcoef_sha256(secp256k1_sha256 *sha) {
 static void secp256k1_musig_keyaggcoef_internal(secp256k1_scalar *r, const unsigned char *pk_hash, secp256k1_ge *pk, const secp256k1_ge *second_pk) {
     secp256k1_sha256 sha;
 
+    VERIFY_CHECK(!secp256k1_ge_is_infinity(pk));
+#ifdef VERIFY
+    VERIFY_CHECK(pk->x.normalized && pk->y.normalized);
+    VERIFY_CHECK(secp256k1_ge_is_infinity(second_pk) || (second_pk->x.normalized && second_pk->y.normalized));
+#endif
+
     if (!secp256k1_ge_is_infinity(second_pk)
           && secp256k1_fe_equal(&pk->x, &second_pk->x)
           && secp256k1_fe_is_odd(&pk->y) == secp256k1_fe_is_odd(&second_pk->y)) {